Medical devices for thermally treating tissue

ABSTRACT

A medical device for treating tissue includes a tissue-contacting surface and a solid state heating element that is thermally coupled to the tissue-contacting surface. The solid state heating element is configured to generate heat to thermally treat tissue.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of, and priority to, U.S.Provisional Patent Application No. 61/708,840, filed on Oct. 2, 2012,and U.S. Provisional Patent Application No. 61/809,061, filed on Apr. 5,2013, the entire contents of each of which are hereby incorporated byreference herein.

BACKGROUND

1. Technical Field

The present disclosure relates to medical devices and, moreparticularly, to medical devices capable of heating tissue to thermallytreat tissue.

2. Background of Related Art

Energy-based medical devices are typically used in conjunction withenergy sources (external energy sources or portable energy sourcesincorporated into the instruments themselves) to apply and control theapplication of energy to tissue to thermally treat, e.g., heat, tissueto achieve a desired tissue effect. Energy-based surgical forceps, forexample, utilize both the mechanical clamping action of the jaw membersand the energy provided by the energy source and delivered to tissue toheat tissue grasped between the jaw members to achieve a desired tissueeffect, e.g., to seal tissue. Various forms of energy, e.g., RF energy,ultrasonic energy, microwave energy, thermal energy, light energy, etc.,may be employed to heat tissue to achieve a desired tissue effect.

SUMMARY

As used herein, the term “distal” refers to the portion that is beingdescribed which is further from a user, while the term “proximal” refersto the portion that is being described which is closer to a user.Further, to the extent consistent, any of the aspects described hereinmay be used in conjunction with any of the other aspects describedherein.

A medical device for treating tissue provided in accordance with aspectsof the present disclosure includes a tissue-contacting surface and asolid state heating element thermally coupled to the tissue-contactingsurface. The solid state heating element is configured to generate heatto thermally treat tissue.

In aspects, the medical device further includes control circuitrycoupled to the solid state heating element. The control circuitry isconfigured to regulate heat generation by the solid state heatingelement

In aspects, the control circuitry and the solid state heating elementare packaged or integrated together. More specifically, the controlcircuitry and the solid state heating element may be part of anintegrated circuit.

In aspects, the medical device further includes one or moretemperature-sensing elements. The one or more temperature-sensingelements are configured to sense a temperature of the solid stateheating element, tissue, and/or another element thermally coupled to thesolid state heating element or tissue.

In aspects, the temperature-sensing element and the solid state heatingelement are packaged or integrated together. More specifically, thetemperature-sensing element and the solid state heating element may bepart of an integrated circuit.

In aspects, the temperature-sensing element is coupled to the controlcircuitry for feedback-based control of the solid state heating element.More specifically, the feedback-based control may be provided to limitthe temperature of the solid state heating element.

In aspects, the medical device further includes a power source coupledto the solid state heating element. The power source is configured tosupply energy to the solid state heating element.

In aspects, the power source is integrated or packaged with the solidstate heating element. The power source may be a battery.

In aspects, the solid state heating element includes one or moretransistors configured to generate heat to thermally treat tissue.

Another medical device for treating tissue provided in accordance withthe present disclosure includes an end effector assembly having firstand second jaw members. One or both of the jaw members is movablerelative to the other between a spaced-apart position and anapproximated position for grasping tissue therebetween. Each of the jawmembers includes a tissue-contacting surface. A solid state heatingelement is thermally coupled to one or both of the tissue-contactingsurfaces. The solid state heating element is configured to generate heatto thermally treat tissue.

In aspects, the medical device further includes control circuitrycoupled to the solid state heating element. The control circuitry isconfigured to regulate heat generation by the solid state heatingelement.

In aspects, the control circuitry and the solid state heating elementare packaged or integrated together.

In aspects, the medical device further includes one or moretemperature-sensing elements. The one or more temperature-sensingelements are configured to sense a temperature of the solid stateheating element, tissue, and/or another element thermally coupled to thesolid state heating element or tissue.

In aspects, the temperature-sensing element is coupled to the controlcircuitry for feedback-based control of the solid state heating element.

In aspects, the solid state heating element is disposed within one ofthe jaw members and the temperature-sensing element is disposed withinthe other of the jaw members.

In aspects, the medical device further includes a power source coupledto the solid state heating element and configured to supply energy tothe solid state heating element.

In aspects, the solid state heating element includes one or moretransistors configured to generate heat to thermally treat tissue.

BRIEF DESCRIPTION OF THE DRAWINGS

Various aspects of the present disclosure are described herein withreference to the drawings wherein like reference numerals identifysimilar or identical elements:

FIG. 1 is a front, perspective view of an endoscopic surgical forcepsconfigured for use in accordance with the present disclosure;

FIG. 2 is a front, perspective view of an open surgical forcepsconfigured for use in accordance with the present disclosure;

FIG. 3 is a front, perspective view of the distal end of a surgicalforceps including reposable jaw members configured for use in accordancewith the present disclosure;

FIG. 4 is a front, perspective view of a surgical tissue clip configuredfor use in accordance with the present disclosure;

FIG. 5A is a transverse, cross-sectional view of an end effectorassembly configured for use with any of the instruments of FIGS. 1-4;

FIG. 5B is a transverse, cross-sectional view of another end effectorassembly configured for use with any of the instruments of FIGS. 1-4;

FIG. 6 is a schematic illustration of power, heating, and controlelectronics configured for use with any of the end effector assembliesof FIGS. 5A-5B;

FIG. 7 is a schematic diagram of a heating circuit configured for usewith any of the end effector assemblies of FIGS. 5A-5B; and

FIG. 8 is a schematic diagram of a control circuit configured for usewith any of the end effector assemblies of FIGS. 5A-5B.

DETAILED DESCRIPTION

There are a wide variety of medical devices that effect the heating oftissue to treat tissue. Tissue heating can be accomplished by Jouleheating, e.g., passing current through tissue; conductive heating, e.g.,placing a heated surface in contact with or in close proximity totissue; dielectric heating, e.g., applying a changing electric field totissue; and/or frictional heating, e.g., creating friction withintissue. With respect to conductive heating of tissue, some of thechallenges include achieving high power densities, a low thermal mass, amanufacturable package, temperature-sensing that is thermally linkedwith the heating elements, and temperature control.

The present disclosure provides for the use of solid state devices,e.g., transistors and other heat generating components of solid statedevices, as a source of heat for conductively heating tissue tothermally treat tissue. Such solid state heating systems can beincorporated into any suitable medical device configured to treattissue. For example, a solid state heating system of the presentdisclosure may be incorporated into: one or both jaw members of asurgical forceps configured to grasp tissue between its jaw members andheat tissue to seal tissue; an ablation probe used to internally heattumors or other tissue to destroy the tumors or other tissue; or on asurface of a medical device configured to be placed over, around, orabout tissue for warming the tissue to provide relief and/or promotehealing. Accordingly, since the present disclosure is not limited to aparticular instrument and/or configuration, the present disclosure willbe described initially in a more general respect, followed by a morespecific description of exemplary configurations.

The solid state heating systems of the present disclosure mayincorporate one or more solid state devices which include, for example,transistors, microprocessors, RAM, semiconductor diodes, integratedcircuits (IC's), etc. Each of these components may themselves includeany suitable type of transistor(s) (e.g., bipolar junction,field-effect, etc.), and/or other solid state heating components (e.g.,resistive elements). The transistors may be configured to operate invarious modes (e.g., switching or active) to generate heat for treatingtissue. More specifically, heat generation by the transistors may becontrolled by changing the operating point of one or more of thetransistors (where the transistors are operating in an active mode), orby changing the switching frequency of one or more of the transistors(where the transistors are operating in a switching mode). This andother control functionality may be provided via analog circuitry,digital logic circuitry, and/or software operating on a microcontroller,the same or another solid state device, or a separate control device orsystem. Transistors based on different materials (e.g., Si, GaAs, SiC,etc.) may also be provided, depending on a particular purpose, e.g.,operating temperature limitations, voltage limits, operating mode,and/or power handling capability. Resistive elements within the solidstate devices may also be specifically provided for generating heat viaresistive loss, and may likewise be made from different materials (e.g.,Si or other suitable metallic materials) depending on a particularpurpose. Further, the solid state devices may be operated at relativelyhigh voltages to allow power to be transmitted at relatively smallercurrents and to reduce transmission losses.

The solid state heating systems of the present disclosure may includecontrol circuitry, one or more temperature sensitive elements coupled tothe control circuitry, and transistors (coupled to or integrated withthe control circuitry) that are utilized to generate heat for heatingtissue. By monitoring the temperature sensitive element, the controlcircuitry can control the transistors, thereby controlling heatgeneration to achieve any desired trace of temperature versus time atthe location of the temperature sensor. Because solid state devices canbe very small, it is possible to achieve tight thermal coupling of thetransistors, the temperature monitoring element, and the target tissueto thereby enable rapid and accurate thermal dosing of the targettissue. Thus, monitoring of the temperature sensitive elementeffectively becomes monitoring of the temperature of the target tissueand of the transistors.

The solid state heating systems of the present disclosure may be formedfrom one or more solid state devices packaged individually and/orpackaged together in one or more sets. Multiple packages of a system maybe provided together on a substrate, may be coupled to one another, ormay be remote from one another. In some embodiments, the package(s)themselves function as a tissue-contacting surface to facilitate theheating and thermal treatment of tissue using the heat generated by thetransistors (or other components) of the solid state devices. Thepackages may further include control circuitry and/or sensor circuitryintegrated therewith. The package(s) may be configured to define anysuitable configuration, e.g., linear, curved, etc., depending on aparticular purpose. Trapezoidal-shaped packages, for example, allowadjacent packages to be fit together in either a linear or curvedconfiguration (depending on their orientation), with minimal spacingbetween adjacent packages, to define a suitable tissue-contactingsurface. However, other suitably shaped packages are also contemplated.In embodiments where the package(s) form a tissue-contacting surface,the packages may further include specific features to facilitate tissuetreatment, e.g., textured surfaces or projections to facilitate graspingtissue, stop features to inhibit contact between surfaces and/or definea gap distance therebetween, etc., and may additionally or alternativelybe etched, cut, grinded, coated with a textured material, film, etc. toprovide a particular surface feature such as, for example, anti-stickcharacteristics.

The solid state heating systems of the present disclosure may be coupledto a separate control system, e.g., a control system that is notintegrated into the heat-generating system. Alternatively, the solidstate heating system may include one or more solid state devicesconfigured for heat-generation and one or more solid state devicesconfigured for control. The one or more heating generating devices andone or more control devices may comprise the same solid state device,may be separate solid state devices integrated into a single package, ormay be separate packages (or standalone devices) of the system. Powermay be provided to the solid state heating system, for example, via abattery (either integrated into the system or separate therefrom), orother power supply.

Transistors of the solid state heating systems of the present disclosuremay be provided in one or more groups and/or solid state devices, withmultiple temperature sensors and/or other control components, to providegreater controllability of the system for achieving more uniform thermaltreatment across tissue or providing different thermal treatments todifferent portions of tissue. Thermally conducting elements integratedinto the solid state devices and/or thermally coupled to one or more ofthe solid state devices of a solid state heating system may also beprovided to distribute heat generated by the heating components tolikewise achieve more uniform thermal treatment across tissue or providedifferent thermal treatments to different portions of tissue.

The solid state heating systems of the present disclosure may integrateor utilize one or more sensing elements such as temperature, pressure,proximity, optical absorption, reflectance, transmittance, Raman, orother types of sensors that measure characteristics of tissue and/or thesystem. These sensing elements may be integrated into the solid statedevices or may be separate therefrom. For example, with respect to asurgical forceps, the solid state devices may be disposed within one ofthe jaw members, while one or more temperature sensors are disposedwithin on or the other jaw member to provide for better control oftissue heating by providing information on the rate at which heat ispenetrating through tissue. Alternatively, solid state devices may beprovided on both jaw members, with either or both including sensingelements.

The solid state devices or solid state heating systems of the presentdisclosure may be utilized, in addition to generating heat for thermallytreating tissue, to provide control and/or power supply functionality.As an alternative to generating heat to heat tissue, the solid statedevices or solid state heating systems may be utilized to minimizethermal gradients between tissue heating components and the rest of themedical device, e.g., via mounting the solid state devices or solidstate heating systems on the opposite side(s) of the device relative tothe tissue-contacting surface(s) thereof, thus allowing for maximumpower delivery to tissue with decreased thermal load on the device.

The solid state heating systems of the present disclosure may utilize orincorporate heat-conducting elements to thermally connect theheat-generating transistors to tissue-contacting surface(s) of a device.Further, active or passive elements may be thermally connected to theheat-generating components or the tissue-contacting surface(s) of adevice to provide cooling. Such elements may include heat sinks that arecooled (rapidly or slowly) by: being thermally coupled to the heatingsystem, ambient air, cooling water, thermo-electric cooling elements,etc.

The heating systems of the present disclosure may be configured toprovide suitable clearance within a device or portion thereof for othermechanical, electrical, or electro-mechanical components, mechanismsand/or systems. This may be accomplished by distributing one or morecomponents of the heating system about the device, e.g., in one or moresolid state devices or packages thereof, and/or distributing multiplesolid state systems about the device. The distributed solid statedevices and/or heating systems may be coupled to one another or may beindependent of one another.

The present disclosure is further exemplified below with respect toparticular devices and end effector assemblies, although the aspects andfeatures of the presently-disclosed solid state heating systems areequally applicable for use with any suitable medical device.

Referring now to FIGS. 1-4, FIG. 1 depicts an endoscopic surgicalforceps 100 for use in connection with endoscopic surgical procedures;FIG. 2 depicts an open surgical forceps 200 contemplated for use inconnection with traditional open surgical procedures; FIG. 3 depicts areposable forceps 300; and FIG. 4 depicts a tissue clip 400. For thepurposes herein, either endoscopic forceps 100, open forceps 200,reposable forceps 300, tissue clip 400, or any other suitable medicaldevice may be utilized in accordance with the present disclosure.Obviously, different electrical and mechanical connections andconsiderations apply to each particular type of device; however, thenovel aspects of the present disclosure and the operatingcharacteristics thereof remain generally consistent regardless of theconfiguration of the device used therewith.

Turning now to FIG. 1, endoscopic forceps 100 defines a longitudinalaxis “A-A” and includes a housing 120, a handle assembly 130, a rotatingassembly 170, a trigger assembly 180 and an end effector assembly 10.Forceps 100 further includes a shaft 112 having a distal end 114configured to mechanically engage end effector assembly 10 and aproximal end 116 that mechanically engages housing 120. End effectorassembly 10, as will be described in detail below, incorporates power,heat-generating, and control electronics therein for conductivelyheating tissue and controlling the heating of tissue to thermally treattissue, thus obviating the need for supplying power, energy, and/orcontrol signals to/from end effector assembly 10. As such, only endeffector assembly 10 need include electrical components, while theremainder of forceps 100 may include only mechanical components, thusreducing the complexity of forceps 100. However, forceps 100 may alsoinclude one or more wires (not shown) extending through shaft 112 toconnect end effector assembly 10 to activation button 190 of housing 120for activating/deactivating the power, heat-generating, and/or controlelectronics. Alternatively or additionally, end effector assembly 10 maybe coupled to control circuitry, an external display, and/or a remotepower source, e.g., an external power source, or a power sourcecontained in another part of forceps 100, for example, handle assembly130.

With continued reference to FIG. 1, handle assembly 130 includes a fixedhandle 150 and a movable handle 140. Fixed handle 150 is integrallyassociated with housing 120 and handle 140 is movable relative to fixedhandle 150. Rotating assembly 170 is rotatable in either direction abouta longitudinal axis “A-A” to rotate end effector 10 about longitudinalaxis “A-A.” Housing 120 houses the internal working components offorceps 100.

End effector assembly 10 is shown attached at distal end 114 of shaft112 and includes a pair of opposing jaw members 11 and 12. One or bothof the jaw members 11 and 12 includes a thermally-conductivetissue-contacting surface 13, 14, respectively, configured to conductthermal energy to tissue grasped between jaw members 11, 12 to thermallytreat, e.g., seal, tissue. End effector assembly 10 is designed as aunilateral assembly, i.e., where jaw member 12 is fixed relative toshaft 112 and jaw member 11 is movable relative to shaft 112 and fixedjaw member 12. However, end effector assembly 10 may alternatively beconfigured as a bilateral assembly, i.e., where both jaw member 11 andjaw member 12 are movable relative to one another and to shaft 112. Insome embodiments, a knife assembly (not shown) is disposed within shaft112 and a knife channel 615, 625 (FIG. 5B) is defined within one or bothjaw members 11, 12 to permit reciprocation of a knife blade (not shown)therethrough, e.g., upon activation of trigger 182 of trigger assembly180. The particular features of end effector assembly 10 will bedescribed in greater detail hereinbelow.

Continuing with reference to FIG. 1, movable handle 140 of handleassembly 130 is ultimately connected to a drive assembly (not shown)that, together, mechanically cooperate to impart movement of jaw members11 and 12 between a spaced-apart position and an approximated positionto grasp tissue between tissue-contacting surfaces 13 and 14 of jawmembers 11, 12, respectively. As shown in FIG. 1, movable handle 140 isinitially spaced-apart from fixed handle 150 and, correspondingly, jawmembers 11, 12 are disposed in the spaced-apart position. Movable handle140 is depressible from this initial position to a depressed positioncorresponding to the approximated position of jaw members 11, 12.

Referring now to FIG. 2, open forceps 200 is shown including twoelongated shafts 212 a and 212 b, each having a proximal end 216 a and216 b, and a distal end 214 a and 214 b, respectively. Forceps 200 isconfigured for use with an end effector assembly 20 that is similar toend effector assembly 10 of forceps 100 (see FIG. 1). More specifically,end effector assembly 20 is attached to distal ends 214 a and 214 b ofshafts 212 a and 212 b, respectively, and includes a pair of opposingjaw members 21 and 22 that are movable relative to one another. Eachshaft 212 a and 212 b includes a handle 217 a and 217 b disposed at theproximal end 216 a and 216 b thereof. Each handle 217 a and 217 bdefines a finger hole 218 a and 218 b therethrough for receiving afinger of the user. As can be appreciated, finger holes 218 a and 218 bfacilitate movement of shafts 212 a and 212 b relative to one anotherfrom an open position, wherein jaw members 21 and 22 are disposed inspaced-apart relation relative to one another, to a closed position,wherein jaw members 21 and 22 cooperate to grasp tissue therebetween.

A ratchet 230 may be included for selectively locking jaw members 21 and22 of forceps 200 relative to one another at various differentpositions. Ratchet 230 may include graduations or other visual markingsthat enable the user to easily and quickly ascertain and control theamount of closure force desired between the jaw members 21 and 22.

With continued reference to FIG. 2, end effector assembly 20, as will bedescribed in detail below, incorporates power, heat-generating, andcontrol electronics therein for conductively heating tissue graspedbetween jaw members 21, 22 to thermally treat, e.g., seal, tissue, thusobviating the need for supplying power, energy, and/or control signalsto/from end effector assembly 20, although end effector assembly 20 offorceps 200 may additionally or alternatively be coupled to a remotepower source (not shown), control circuitry (not shown), and/or anexternal display (not shown). One or both of the jaw members 21 and 22further includes a thermally-conductive tissue-contacting surface 23,24, respectively, configured to facilitate the conduction of thermalenergy to tissue grasped between jaw members 21, 22 to treat, e.g.,seal, tissue.

Similar to forceps 100 (FIG. 1), forceps 200 may further include a knifeassembly (not shown) disposed within either of shafts 212 a, 212 b and aknife channel 615, 625 (FIG. 5B) defined within one or both jaw members21, 22 to permit reciprocation of a knife blade (not shown)therethrough.

Turning now to FIG. 3, reposable forceps 300 may be configured as anopen forceps, e.g., similar to forceps 200 (FIG. 2), an endoscopicforceps, e.g., similar to forceps 100 (FIG. 1), or in any other suitableconfiguration. Reposable forceps 300 includes an end effector assembly30 similar to end effector assemblies 10, 20 (FIGS. 1, 2, respectively),except that jaw members 31, 32 each include a fixed jaw frame 31 a, 32 aand a removable jaw body 31 b, 32 b, respectively. Jaw bodies 31 b, 32 bare removably engagable with respective jaw frames 31 a, 32 a andincorporate power, heat-generating, and control electronics therein forconductively heating tissue to thermally treat, e.g., seal, tissue. Assuch, depending on a particular purpose, a pair of jaw bodies 31 b, 32 bhaving a particular configuration, e.g., including particularlyconfigured power, heat-generating, and/or control electronics, may beselected and engaged to jaw frames 31 a, 31 b, respectively. Thisconfiguration not only provides for customization of forceps 300, butalso obviates the need for supplying power, energy, and/or controlsignals to jaw bodies 31 b, 32 b. Further, this configuration, whereinthe electrical components are fully disposed within jaw bodies 31 b, 32b, allows the remainder of forceps 300 to include only mechanicalcomponents, thus reducing the complexity of forceps 300 and obviatingthe need for releasable electrical couplings between jaw bodies 31 b, 32b and respective jaw frames 31 a, 32 a. Either or both of jaw bodies 31b, 32 b further includes a thermally-conductive tissue-treating surface33, 34, respectively, adapted to conduct heat to tissue grasped betweenjaw members 31, 32 to thermally treat, e.g., seal, tissue.

Referring now to FIG. 4, tissue clip 400 is an integrated or stand-aloneend effector assembly including first and second jaw members 41, 42,respectively, coupled to one another by a flexible joint 43, althoughjaw members 41, 42 may alternatively be coupled to one another by ahinge, pivot, or any other suitable mechanism. Flexible joint 43 permitsjaw members 41, 42 to move relative to one another between spaced-apartand approximated positions for grasping tissue therebetween. Jaw members41, 42 of tissue clip 400 each further include a thermally-conductivetissue-contacting surface 44, 45, respectively. Power, heat-generating,and control electronics are disposed within either or both of jawmembers 41, 42 for providing power to tissue clip 400, converting thepower into thermal energy, and controlling the conduction of thermalenergy to thermally-conductive tissue-contacting surfaces 44, 45 of jawmembers 41, 42, respectively, to thermally treat, e.g., seal, tissuegrasped between jaw members 41, 42. That is, tissue clip 400 is a fullyintegrated tissue-treating unit incorporating all the necessarymechanical and electrical components therein for conductively heatingtissue to thermally treat tissue. A latch mechanism 49 including firstand second latch components 49 a, 49 b disposed on first and second jawmembers 41, 42, respectively, may also be provided for selectivelylocking jaw members 41 and 42 relative to one another in variousdifferent positions.

Turning now to FIGS. 5A-5B, various embodiments of end effectorassemblies 500, 600, configured for use with forceps 100 (FIG. 1),forceps 200 (FIG. 2), forceps 300 (FIG. 3), and/or tissue clip 400 (FIG.4) are shown. Although shown as separate embodiments, any or of all ofthe features of end effector assemblies 500, 600, to the extent thatthey are consistent, may similarly be used in conjunction with the otherend effector assembly 500, 600. Further any of the features detailedabove may be incorporated into end effector assemblies 500, 600 inaddition to or as an alternative to the features detailed below.

Continuing with general reference to FIGS. 5A-5B, each end effectorassembly 500, 600 incorporate heat-generating systems and controlsystems. End effector assembly 500 further incorporates a power system,while end effector assembly 600 is configured to couple to a remotelydisposed power system, e.g., exteriorly of the surgical instrument or inanother portion of the surgical instrument such as, for example, thehandle assembly. The heat-generating systems of end effector assemblies500, 600 are formed from one or more solid state devices incorporatedinto, forming, packaged to define, or otherwise disposed in thermalcommunication with the tissue-contacting surface(s) of one or both ofthe jaw members thereof to facilitate conductive heating of tissuegrasped between the jaw members to thermally treat, e.g., seal, tissue.The control systems may likewise be incorporated into one or more solidstate devices, packaged together or separate from the heat-generatingsystems. As will be described in greater detail below, by incorporatingthe power system, heat-generating system, and/or control system into theend effector assembly and thermally coupling these systems to thetissue-contacting surfaces of the jaw members, the need for externalpower, heat-generating, and/or control electronics is obviated. Further,the use of a solid state heat-generating and/or control systems forconductive heating of tissue obviates the need to produce electricalenergy, e.g., RF energy, microwave energy, etc., for transmissionthrough tissue, thereby reducing the overall power requirements andcomplexity of the end effector assembly 500, 600. As such, sufficientlysmall power sources, e.g., batteries capable of being fully disposedwithin the end effector assembly 500, 600, miniature solid stateheat-generating elements, e.g., transistor-based heating elements, andminiature solid state control elements, can be utilized.

With reference to FIG. 5A, end effector assembly 500 includes first andsecond jaw members 510, 520, respectively, each including a jaw housing511, 521 and a thermally-conductive tissue-contacting surface 512, 522,respectively. Jaw housings 511, 521 are formed from insulative materialsand are supported on a respective jaw frame 513, 523. Jaw frames 513,523 are coupled to one another, e.g., via a pivot (not shown), to permitmovement of jaw members 510, 520 relative to one another between aspaced-apart position and an approximated position for grasping tissuetherebetween. Tissue-contacting surfaces 512, 522 are disposed on jawhousings 511, 521, respectively, and are configured to grasp tissuetherebetween upon movement of jaw members 510, 520 to the approximatedposition. Either or both of the tissue-contacting surfaces, e.g.,tissue-contacting surface 512, is thermally coupled to one or more solidstate heat-generating elements 530 such that heat produced byheat-generating elements 530 may be conducted to tissue-contactingsurface 512 (and/or tissue-contacting surface 522) for conductivelyheating tissue grasped between jaw members 510, 520 to thermally treat,e.g., seal, tissue. One example of a solid state, transistor-basedheat-generating element 530 is described below (see FIG. 7), althoughother suitable solid state heat-generating elements 530 may also beprovided as an alternative or in addition to transistor-based heatingelements.

One of the jaw members, e.g., jaw member 510, may include a powersource, e.g., a battery 540, disposed therein that is coupled to heatgenerating elements 530 for providing power to end effector assembly500, e.g., for powering heat-generating elements 530. Further, one ofthe jaw members, e.g., jaw member 510, may include a control unit 550disposed therein and coupled to either or both of heat-generatingelements 530 and battery 540 for controlling heat-generating elements530 and, thus, for controlling the heating of tissue grasped between jawmembers 510, 520, as will be described in greater detail below. Controlunit 550 may further be configured to control other components of themedical device associated with end effector assembly 500.

Continuing with reference to FIG. 5A, one or both of the jaw members,e.g., jaw member 510, further includes a substrate 514 disposed thereinand positioned adjacent to and in thermal communication with thetissue-contacting surface 512 thereof. Substrate 514 incorporates,contains, mounts, supports, or otherwise couples to solid-stateheat-generating elements 530 and/or solid state control unit 550.Substrate 514 may be the substrate upon which heat generating elements530 and/or control unit 550 is formed, e.g., a silicon wafer.Alternatively or additionally, substrate 514 may be formed at leastpartially from a printed circuit board (PCB), a ceramic substrate, FR4substrate, rigid plastic or composite substrate, flexible substrate(e.g., a flex circuit including polyimide, PEEK, polyester, PET, etc.),or any other suitable substrate or assembly that incorporates, mounts,receives or couples to heat-generating elements 530 and/or control unit550. Substrate 514 may further be configured to facilitate theconduction or transfer of heat from the heat-generating elements 530 totissue-contacting surface 512, e.g., substrate 514 may be formed from athermally-conductive material in contact with tissue-contacting surface512 or may otherwise be configured to facilitate thermal conductionbetween heat-generating elements 530 and tissue-contacting surface 512(e.g., via wires, traces, other conductive elements, etc.). Substrate514 may also define or incorporate the tissue-contact surface 512therein or thereon and, in such embodiments, may further be configuredto include any of the features detailed above. Insulative jaw housing511 encapsulates substrate 514 such that substrate 514 is thermallycoupled to tissue-contacting surface 512, but is otherwise surrounded bya thermally insulating material.

Battery 540 and/or control unit 550 may likewise be incorporated into,mounted, or otherwise coupled to substrate 514, similarly as detailedabove with respect to heat-generating elements 530. More specifically,heat-generating elements 530, battery 540, and/or control unit 550 maybe formed on substrate 514 as one or more solid state devices, e.g.,integrated circuits (ICs) on a PCB, multi-chip modules (MCMs) packagedin a ceramic (or other suitable) substrate, System-in-Package (SiP)modules, a microprocessor, or other suitable electronics for generatingheat to conductively heat tissue and control the heating of tissue.

Coupling battery 540, control unit 550, and/or heat-generating elements530 together within one or more solid state devices on or in a substrateor package within end effector assembly 500 itself, e.g., withoutrequiring external power or control electronics, facilitatescustomization for each particular procedure to be performed, which isparticularly useful with respect to reposable forceps 300 (FIG. 3) andstand-alone tissue clips 400 (FIG. 4). Referring to FIG. 3, in additionto FIG. 5A, with regard to reposable forceps 300, rather than requiringan entirely new or different instrument customized for a particularprocedure, all that is required is a new or different pair of jaw bodies31 b, 32 b having a desired configuration of power, heat-generating,and/or control electronics. In other words, various different jaw bodies31 b, 32 b may be provided for use with reposable forceps 300, eachhaving a differently configured control unit and/or heat-generatingelement(s) to, for example, provide various different thermal treatmentparameters and/or sealing algorithms. Accordingly, a generic reusableinstrument configured to engage a desired set of jaw bodies 31 b, 32 bmay be customized in accordance with the particular procedure to beperformed. Further, when it is desired to update/upgrade the controlunit 550, only new jaw bodies 31 b, 32 b are required, rather than anentirely new instrument. Jaw bodies 31 b, 32 b may also be configuredfor use with various different instruments, e.g., an endoscopic forcepssimilar to forceps 100 (FIG. 1) or an open forceps similar to forceps200 (FIG. 2), depending on a particular purpose. Similarly with regardto tissue clips 400 (FIG. 4), various different tissue clips 400 (FIG.4), each having a control unit and heat-generating element configured,e.g., having particular thermal treatment parameters and/or sealingalgorithms, in accordance with a particular procedure, type/size oftissue, etc., may be provided. Exemplary control circuitry forincorporation into the control unit 550 of the various jaw bodies 31 b,32 b and/or tissue clips 400 (FIG. 4) are described below.

In addition to facilitating customization, coupling control unit 550,and/or heat-generating elements 530 together within one or more solidstate devices on or in a substrate or package allows for a minimalnumber of required external connections. For example, where battery 540is not provided, such an integrated solid state device or device(s) in apackage may require only three external connections: power, ground(return), and a control line for manually activating the device ormanually terminating operation (see FIG. 5B). Where battery 540 isprovided, only the control line may be required. The control line mayfurther be configured to enable calibration, programming, synchronizing,updating, selecting different operating modes, etc.

With continued reference to FIG. 5A, control unit 550, as mentionedabove, is coupled to battery 540 and/or heat-generating elements 530, ormay include or be integrated with battery 540 and/or heat-generatingelements 530 in one or more solid state devices, via packaging, or asubstrate. Control unit 550 may include solid state or other componentsincluding, for example, logic or processing circuitry, e.g.,microprocessors, field-programmable gate arrays (FPGAs), discrete logiccircuits, etc.; timing circuitry; and/or other control circuitry forcontrolling, e.g., turning on/off, heat-generating elements 530 inaccordance with one or more parameters, algorithms, or cycles. Further,control unit 550 may include or be coupled to one or more sensingelements 560, e.g., temperature sensors, pressure sensors, tissueproperty sensors, etc. Sensing element 560, as will be described ingreater detail below, may be configured, for example, to sense thetemperature and/or other properties of tissue grasped between jawmembers 510, 520 such that control unit 550, in conjunction with sensingelement 560, can control the thermal treatment of tissue via a feedbackloop. Control unit 550, as mentioned above, may include one or moresolid state devices, e.g., ICs, incorporated into substrate 514 or apackage, or may assume any other suitable configuration, such as thosementioned above. The particular configuration of the control circuitryof the control unit 550 and/or the type and configuration of sensingelements 560 used therewith may be selected in accordance with theparticular procedure to be performed, the type/size of tissue to betreated, and/or other factors. As mentioned above, various reposable jawbodies 31 b, 32 b (FIG. 3) and/or various tissue clips 400 (FIG. 4) maybe provided, each incorporating a differently configured control unit550 adapted for use in a particular procedure (or procedures).

Referring to FIG. 5A in conjunction with FIG. 1, the use and operationof end effector assembly 500 in conjunction with forceps 100 isdescribed. Although the use and operation of end effector assembly 500is described with respect to forceps 100, end effector assembly 500 maybe similarly configured for use with forceps 200, forceps 300, or tissueclip 400 (FIGS. 2, 3, and 4, respectively).

Initially, with jaw members 510, 520 disposed in the spaced-apartposition, end effector assembly 500 is maneuvered into position suchthat tissue to be grasped and thermally treated, e.g., sealed, isdisposed between jaw members 510, 520. Next, movable handle 140 isdepressed, or pulled proximally relative to fixed handle 150 such thatjaw member 510 is pivoted relative to jaw member 520 from thespaced-apart position to the approximated position to grasp tissuetherebetween. More specifically, upon actuation of movable handle 150, adrive assembly (not shown) is activated such that a drive bar (notshown) is translated proximally through shaft 112, urging jaw member 510to pivot relative to jaw member 520 from the spaced-apart position tothe approximated position.

Once disposed in the approximated position grasping tissue betweentissue-contacting surfaces 512, 522 of jaw members 510, 520,respectively, control unit 550 is activated, e.g., manually viadepression of activation switch 190 of forceps 100 or automatically uponapproximation of jaw members 510, 520 (or upon occurrence of some othercondition) as determined by control unit 550 and sensing elements 560,such that power is supplied from battery 540 to heat-generating elements530. Upon activation, e.g., upon supply of electrical power toheat-generating elements 530, heat-generating elements 530 produce heatthat is conducted to tissue grasped between jaw members 510, 520 viasubstrate 514 and tissue-contacting surfaces 512, 514 to conductivelyheat tissue. Control unit 550, as mentioned above, and as will bedescribed in greater detail below with reference to FIG. 8, may beconfigured to control the heating of tissue in conjunction with sensingelements 560 via feedback control, using a timing circuit, e.g.,maintaining heat-generating elements 530 at a pre-determined temperaturefor a pre-determined time, or via any other suitable control mechanismto thermally treat tissue as desired.

With respect to tissue sealing in particular, the compression of tissuebetween jaw members 510, 520 brings tissue walls together and theconductive heating of tissue causes denaturizing and mixing of collagenand elastin to form an effective tissue seal. Heating of tissue to thetarget temperature for forming an effective tissue seal is dependent ona number of factors including the compressive force applied to tissue byjaw members 510, 520, the size and/or composition of tissue, the amountof thermal energy supplied to tissue, and other factors. Control unit550 of end effector assembly 500 may thus be configured to control theheating of tissue in accordance with one or more of these factors, suchthat formation of an effective tissue seal (or otherwise effectivelytreating tissue) can be achieved. That is, control unit 550 andheat-generating elements 530 cooperate to start, regulate, and end theheating of tissue to facilitate formation of an effective tissue seal.Further, control unit 550 may be configured to individually and/orcollectively control heat-generating elements 530 to achieve a moreuniform tissue seal or other desired tissue effect. As can beappreciated, with respect to tissue heating for other purposes, theparticular control settings and configuration of control unit 550 may bevaried.

As mentioned above, control unit 550 may further include or may becoupled to one or more sensing elements 560 disposed on or along jawmember 510 (and/or jaw member 520) that are configured to automaticallysense various properties of tissue or jaw members 510, 520 including,but not limited to: tissue type, tissue clarity, tissue compliance,tissue temperature, temperature of jaw members 510, 520, temperature ofheat-generating elements 530, temperature of substrate 514, watercontent in tissue, opening angle of jaw members 510, 520, water motilityin tissue, and/or jaw member closure pressure. Sensing elements 560provide measurements to control unit 550, thus allowing control unit 550to control heat-generating elements 530, e.g., to turn on/off one ormore of heat generating elements 530, to heat tissue in accordance withthe one or more properties of tissue and/or jaw members 510, 520 (and/orany of the components thereof) detected by sensing elements 560.

At the completion of tissue sealing, or other tissue treatment, a knife(not shown) may be advanced from shaft 112 of forceps 100 between jawmembers 510, 520 to cut the previously-sealed tissue graspedtherebetween, e.g., upon actuation of trigger 182 of trigger assembly180. Alternatively, in embodiments where the configuration of thecontrol unit 550 and heat-generating elements 530 so provides, e.g.,wherein control unit 550 incorporates a thermal cutting algorithm orthermal cutting parameters, heat generating-elements 530 may beconfigured to conduct thermal energy to tissue to thermally dissecttissue along the previously-formed tissue seal. Thereafter, or inembodiments where tissue cutting is not desired, jaw members 510, 520may be returned to the spaced-apart position to release the sealedand/or divided tissue, e.g., via moving movable handle 140 back to theinitial position.

Referring now to FIG. 5B, another embodiment of an end effector assembly600 configured for use with forceps 100 (FIG. 1), forceps 200 (FIG. 2),forceps 300 (FIG. 3), and/or tissue clip 400 (FIG. 4) is shown. Endeffector assembly 600 is similar to end effector assembly 500 (FIG. 5A)and may includes any of the features thereof, and vice versa. Forpurposes of brevity, only the differences between end effector assembly600 and end effector assembly 500 (FIG. 5A) will be described in detailhereinbelow.

End effector assembly 600 includes first and second jaw members 610,620, respectively, each including a jaw housing 611, 621 supported on ajaw frame 613, 623 and a pair of tissue-contacting surfaces 612 a, 612 band 622 a, 622 b disposed on respective jaw housings 611, 621. One orboth of jaw members 610, 620 is movable relative to the other between aspaced-apart position and an approximated position for grasping tissuetherebetween. The tissue-contacting surfaces 612 a, 612 b and 622 a, 622b of each jaw member 610, 620 are disposed on either side of arespective knife channel 615, 625 extending longitudinally through therespective jaw member 610, 620, and are configured to conduct heat totissue grasped between jaw members 610, 620 to thermally treat, e.g.,seal, tissue.

Continuing with reference to FIG. 5B, each jaw member 610, 620 includesa pair of packages 614 a, 614 b and 624 a, 624 b disposed on either sideof knife channels 615, 625, respectively, that define the respectivetissue-contacting surfaces 612 a, 612 b and 622 a, 622 b of jaw members610, 620. As an alternative to packages 614 a, 614 b and 624 a, 624 b,substrates defining tissue-contacting surfaces 612 a, 612 b and 622 a,622 b may alternatively be provided.

Each package 614 a, 614 b and 624 a, 624 b incorporates one or moresolid state heat-generating elements 630 and one or more solid statecontrol units 650 for controlling the respective heat-generatingelements 630. Packages 614 a, 614 b and 624 a, 624 b are coupled to anexternal power source (not explicitly shown) via wires 641, 642 and 643,644, respectively. Sensing elements (not explicitly shown) may also beprovided for use in conjunction with one or more of packages 614 a, 614b, 624 a, 624 b. The heat-generating element(s) 630 corresponding toeach package 614 a, 614 b and 624 a, 624 b may be independently orcollectively operated to achieve a desired tissue effect.

Turning now to FIGS. 6-8, and with initial reference to FIG. 6,schematics of an electronics system 700, e.g., the power source 710, theheat-generating element 720, and the control unit 750, configured foruse with end effector assemblies 500, 600 (FIGS. 5A-5B, respectively),or any other suitable end effector assembly, are shown and described. Asshown in FIG. 6, and as mentioned above, the electronics system 700 ofeach end effector assembly generally incorporates a power source 710,e.g., a battery, one or more heat-generating elements 720, and a controlunit 750 that are coupled to one another (in any suitable configuration,such as those detailed above) to conductively heat and control theheating of tissue to achieve a desired tissue effect, e.g., to sealtissue.

Turning now to FIG. 7, in conjunction with FIG. 6, one embodiment of aheat-generating circuit 730 for the heat-generating element 720 is shownconfigured as a constant-temperature heat source. Heat-generatingcircuit 730 is formed as a transistor-based, solid state heating deviceconfigured to receive power from power source 710 and to produce heatfor conduction to tissue to thermally treat tissue. More specifically,heat-generating circuit 730 includes a power supply V_(cc) that iscoupled to power source 710 for receiving power therefrom, apower-dissipating, e.g., heat-producing, Field-Effect Transistor (FET)FET₁, e.g., a Metal-Oxide-Semiconductor Field-Effect transistor (MOSFET)or a junction gate field-effect transistor (JFET), a temperature-controlcircuit 732, and a biasing circuit 734. The biasing circuit 734 isconfigured to operate FET₁ in a highly dissipating manner to produceheat for conductively heating tissue. The temperature-control circuit732 includes a positive temperature coefficient thermistor PTC₁thermally coupled to FET₁ for substantially maintaining FET₁ at aconstant temperature. That is, as FET₁ heats up, PTC₁ likewise heats up,thereby increasing in resistance and reducing the drive to FET₁ byswitching ON the transistor Tr. When the FET₁ cools down, PTC₁ likewisecools down and its resistance decreases such that the drive to FET₁ isincreased by switching OFF the transistor Tr. Thus, FET₁ can be heatedto and maintained at a substantially constant temperature, or within asufficiently narrow temperature range.

Turning now to FIG. 8, in conjunction with FIGS. 6 and 7, one embodimentof a solid state-implemented control circuit 760 for the control unit750 is shown configured for electrical coupling between the power source710 and heat-generating element 720 for controlling, e.g., turningON/OFF, the supply of electrical energy to heat-generating element 720.Control circuit 760 is configured as an analog timing circuit forheating tissue to a pre-determined temperature for a pre-determinedamount of time, although other suitable control circuits are alsocontemplated utilizing either analog or digital methods. Morespecifically, control circuit 760 includes a sensing element 762(similar to sensing element 560 (FIG. 5A), above), e.g., a PTCthermistor PTC₂, configured to sense the temperature of tissue to bethermally treated, and a FET FET₂ that is coupled between power source710 and heat-generating element 720 for turning ON/OFF the supply ofpower to heat-generating element 720 such that tissue in thermal contactwith temperature-sensing element 762 can be heated to a targettemperature and maintained at or above that target temperature for apre-determined amount of time to facilitate thermal tissue treatment,e.g., tissue sealing.

In one implementation, control circuit 760 may be used with aconstant-temperature heat-generating element 720, although controlcircuit 760 may also be used with other suitable heat-generatingelements 720. With regard to constant temperature heat-generatingelement 720, temperature-sensing element 762 may be positioned on or inthe jaw member opposing the jaw member containing heat-generatingelement 720. In this configuration, upon activation of heat-generatingelement 720, tissue contacting the jaw member containing heat-generatingelement 720 is heated relatively quickly to and is maintained at thepredetermined “constant” temperature. Heat-generating element 720 ismaintained at this predetermined “constant” temperature untiltemperature-sensing element 762, which is disposed on or in the opposingjaw member, has been sufficiently heated, indicating that tissueadjacent temperature-sensing element 762 has been sufficiently heated.When sufficiently heated, indicating the end the heating cycle, controlcircuit 760 operates to turn OFF the supply of power to heat-generatingelement 720.

More specifically, in use, momentary contact switch S is used to zerothe voltage across capacitor C, turning on FET₂, and initiating heatingby heat-generating element 720. Capacitor C charges very slowly throughresistor R₂, which defines an upper bound on the duration of the heatingcycle. As temperature-sensing element 762 is heated, its resistanceincreases, raising the voltage of the node between it and resistor R₁and eventually allowing capacitor C to be charged through diode D with atime constant determined by the capacitance and the resistance of thevoltage divider formed by R₁ and temperature-sensing element 762. Thisrate is typically much faster than the charging of capacitor C via R₂.The increasing voltage across capacitor C eventually turns off FET₂,ending the heating cycle.

Put more generally, timing circuit 760 is activated (and the charging ofcapacitor C begins) once tissue to be thermally treated reaches thetarget temperature, as sensed by sensing element 762. Capacitor C ischarged to equilibrium (over a pre-determined amount of time), at whichpoint FET₂ is switched OFF to cut off the supply of power toheat-generating element 720. That is, timing circuit 760 turns OFFheat-generating element 720 once tissue has been heated to the targettemperature for a pre-determined amount of time. Thermistor PTC₂,resistors R₁, R₂, and capacitor C may be configured in accordance with adesired target temperature and “on time” of the control circuit 760. Thetarget temperature and “on time” may depend on the particular procedureto be performed, the type/size of tissue to be thermally treated and/orother factors. As mentioned above, various different jaw bodies 31 b, 32b of a reposable forceps 300 (see FIG. 3) and/or various differenttissue clips 400 (FIG. 4) may be provided, each configured for aparticular procedure (or procedures), e.g., each incorporating a controlcircuit 760 having a target temperature and “on time” adapted for aparticular procedure (or procedures).

Momentary contact switch S, which, as mentioned above, is used to zerothe voltage across capacitor C, turn on FET₂, and initiate heating byheat-generating element 720, may be coupled to activation switch 190(FIG. 1) of forceps 100 for manually controlling the initiation of theheating cycle upon activation of activation switch 190, while completionof the heating cycle, e.g., once tissue has been heated to the targettemperature for the pre-determined amount of time, is automaticallycontrolled via control circuit 760.

From the foregoing and with reference to the various figure drawings,those skilled in the art will appreciate that certain modifications canalso be made to the present disclosure without departing from the scopeof the same. While several embodiments of the disclosure have been shownin the drawings, it is not intended that the disclosure be limitedthereto, as it is intended that the disclosure be as broad in scope asthe art will allow and that the specification be read likewise.Therefore, the above description should not be construed as limiting,but merely as exemplifications of particular embodiments. Those skilledin the art will envision other modifications within the scope and spiritof the claims appended hereto.

What is claimed is:
 1. A medical device for treating tissue, comprising:an end effector assembly including first and second jaw members, atleast one of the jaw members movable relative to the other between aspaced-apart position and an approximated position for grasping tissuetherebetween, at least one of the jaw members including: a jaw housing;and an integrated circuit package disposed on the jaw housing anddefining a tissue-contacting surface thereof, the integrated circuitpackage including: a solid state heating element including at least onetransistor configured to generate heat to thermally treat tissue; abattery configured to supply energy to the at least one transistor ofthe solid state heating element such that the at least one transistorgenerates heat to thermally treat tissue; and control circuitryconfigured to regulate the supply of energy from the battery to the atleast one transistor to thereby regulate heat generation by the solidstate heating element.
 2. The medical device according to claim 1,further comprising at least one temperature-sensing element configuredto sense a temperature of at least one of: the solid state heatingelement, tissue, and another element thermally coupled to the solidstate heating element or tissue.
 3. The medical device according toclaim 2, wherein the control circuitry is coupled to thetemperature-sensing element for feedback-based control of the supply ofenergy from the battery to the at least one transistor.
 4. The medicaldevice according to claim 2, wherein the solid state heating element isdisposed within one of the jaw members and wherein thetemperature-sensing element is disposed within the other of the jawmembers.